Medication adherence and healthcare disparities: impact of statin co-payment reduction

Am J Manag Care. 2015 Oct;21(10):696-704.


Objectives: Minority patients have lower rates of cardiovascular medication adherence, which may be amenable to co-payment reductions. Our objective was to evaluate the effect of race on adherence changes following a statin co-payment reduction intervention.

Study design: Retrospective analysis.

Methods: The intervention was implemented by a large self-insured employer. Eligible individuals in the intervention cohort (n = 1961) were compared with a control group of employees of other companies without such a policy (n = 37,320). As a proxy for race, we categorized patients into tertiles based on the proportion of black residents living in their zip code of residence. Analyses were performed using difference-in-differences design with generalized estimating equations.

Results: Prior to the new co-payment policy, adherence rates were higher for individuals living in areas with fewer black residents. In multivariable models adjusting for demographic factors, clinical covariates and baseline trends, the co-payment reduction increased adherence by 2.0% (P = .14), 2.1% (P = .15) and 6% (P < .0001) for intervention patients living in areas with the bottom, middle and top tertiles of the proportion of black residents. These results persisted after adjusting for income.

Conclusions: Co-payment reduction for statins preferentially improved adherence among patients living in communities with a higher proportion of black residents. Further research is needed on the impact of value-based insurance design programs on reducing racial disparities in cardiovascular care.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Black or African American / statistics & numerical data
  • Cardiovascular Diseases / complications
  • Cardiovascular Diseases / economics
  • Cardiovascular Diseases / ethnology
  • Cost Sharing / economics
  • Cost Sharing / standards
  • Diabetes Complications / economics
  • Diabetes Complications / ethnology
  • Diabetes Complications / prevention & control
  • Female
  • Health Benefit Plans, Employee / economics*
  • Health Benefit Plans, Employee / standards
  • Health Expenditures*
  • Health Status Disparities*
  • Heart Diseases / economics
  • Heart Diseases / ethnology
  • Heart Diseases / prevention & control*
  • Humans
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / economics*
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / therapeutic use
  • Insurance, Pharmaceutical Services / economics*
  • Insurance, Pharmaceutical Services / standards
  • Male
  • Medication Adherence / ethnology*
  • Medication Adherence / statistics & numerical data
  • Middle Aged
  • Minority Health / economics
  • New Jersey / epidemiology
  • Poverty Areas
  • Retrospective Studies


  • Hydroxymethylglutaryl-CoA Reductase Inhibitors